If there was ever any doubt as to how openly gamblers were allowed to operate at major league ballparks in the early 20th century, the notorious Gamblers Riot at Boston’s Fenway Park on June 16, 1917, should have expelled it forever. That business went on as usual after such a public spectacle illustrates just how little attention American League president Ban Johnson and other baseball officials paid to the gambling menace that would soon threaten to destroy the game with the Black Sox Scandal.

Looking back nearly a century later, it’s hard to believe the Fenway Park Gamblers Riot actually happened. The closest comparison for sports fans in the 21st century might be the infamous “Malice at the Palace,” a 2004 brawl during an NBA game in Auburn Hills, Mich., that spilled into the stands. But while the NBA took measures afterward to increase security and punish the participants, baseball officials in 1917 only increased their rhetoric after Boston gamblers invaded the field (twice!) and fought with opposing Chicago White Sox players.

The Sporting News called it “one of the most disgraceful scenes ever witnessed in a major league ball park.”